MGL Electronic circuit breaker module
User and installation manual
General The ECB module provides 8 electronic circuit breakers. All breakers have the same characteristics: DC current up to 10A (programmable via dipswitch profile selection) or via an external device. Suitable for 12V or 24V DC aircraft power systems. Highly reliable, fault tolerant design – continues to operate even in case of total internal electronics failure. Can be used as a stand-alone device or it can be connected to an EFIS system. In case of connection to an EFIS system, EFIS can show individual DC currents through each breaker, breaker states and in case this is allowed via dipswitch selection, the EFIS may also control breakers. EFIS can setup breaker trip currents in 0.1A steps up to10A as well as trip reaction times in steps of 0.01 seconds. Trip reaction times are further modulated by the amount of overcurrent (I.e. Times are shorter the higher the current above the trip limit). Breakers may be paired or tripled to create breakers of 20A or 30A capability. Very high quality semiconductor switches are used offering very low on-resistance and consequent low self heating. Further to this switches are protected against reverse polarity, ultimate over-current and over-temperature conditions. Each breaker output is available on a screw terminal and features a built in LED indicator connected to the breaker output. Further to this a stainless steel M6 bolt is provided as input power terminal. This terminal also has a built in LED connected to it to show availability of power. Breakers are controlled via low current, low voltage latching switches and/or via an external device such as an EFIS. Each breaker offers two status outputs intended for panel mount or switch mount LEDs. These are typically used for red and green LEDs or dual color red/green LEDs. The green LED shows the switch status (on/off) while the red LED shows the breaker fault status. It is also possible to use just a single LED such as is used with many attractive panel mount switches. In this case the LED will be solid ON if the breaker is on and will flash if the breaker is switched on but tripped (faulted). The LED is off if the breaker is switched off. Several profiles are available to support typical landing light “WigWag”. In this mode a landing light has two breakers (or four with breaker doubling), one for the left and one for the right wing. The breakers have three operational states: Both off, alternating on/off and both on. The “WigWag” function is a particularly effective way of increasing visibility of small aircraft under way at large airports where a multitude of lights may obscure these craft. A LED flasher profile is available which uses two breakers to create bursts of three short flashes on each breaker. The breakers are phased such that none of the two breakers are on at the same time. This mode allows direct driving of high brightness 12V LED lamps to replace strobes etc.
The breaker in detail This image shows a block diagram of each of the 8 equivalent breakers in the system.
12V or 24V DC input up to 60A total current
Low impedance semiconductor switch On resistance 0.006 ohms Up to 10A output
To other breakers
Current monitor Microprocessor
Protection Current > 45A Temperature > 165 C
CAN and RS232 interfaces
Override circuit if Microprocessor fails
Flat ribbon cable split into sections of 4 conductors Fault LED or combined status/Fault LED
System ground
Latching switch or bridge if only EFIS control desired
Switch status LED controlled by hardware
The LEDs The left LED reflects the status of the switch. Normally a green LED is used for this. This LED may be omitted and only the Fault LED used. In this case please reprogram the unit (either via dipswitch or via EFIS) to use a single LED. In this case use a green or blue LED connected to the Fault LED line and leave the switch status line unconnected. In single LED mode the Fault LED will flash if the breaker has tripped, otherwise it will be either on or off to reflect the state of the switch.
The Override circuit The override circuit monitors the microprocessor. If the microprocessor fails the override circuit takes over within 2 mS and enables the switch. In the override state the external switch dictates the breaker state and if bridged the breaker will be switched on. Breaker trip current will be set to 45A. The breaker will also trip if the internal temperature of the breaker reaches 165 degrees C. Notes: If Landing lights are used with WigWag, in override mode the landing lights will be switched on if the panel switch is on. No Wigwag will take place. If burst flash is used, the outputs will be on if the panel switch is on. If high power LEDs are used, please ensure they have adequate protection and will not be damaged by permanent power applied.
Power sequencing On start up of the ECB any breakers that have control inputs grounded (“on” state) will have the actual breaker closure sequenced where breaker 1 switches on first, followed by other breakers in sequence. Interval between breakers is 0.1 second. This feature limits the start current surge in a typical aircraft system. Note: In case of breaker override (internal ECB microprocessor not operational) this sequencing cannot happen and all breakers that have their control inputs grounded will switch on at the same time.
Breakers controlled only by external system If it is desired that breakers are only controlled by an external system, provide a bridge in place of the switch. You can consider bridging the connector itself if no LEDs are needed. This image shows an example:
Notes: With breaker switches bridged, in case of a microprocessor failure (ECB) all bridged breakers will be “ON”. No control from external devices (EFIS systems etc) will be possible in this case. Please consider this in your system design.
Breakers controlled by ECB panel switches and external system No further action needs to be done in this case. Wire the panel switches as normal to control the breakers. If an external system is connected it can switch breakers provided the panel switch is “on”. If panel switch is “off”. Breaker is “off” regardless of external control, external switch commands are ignored. If panel switch is “on”. Breaker is “on” - external system can control breaker (switch on and off once the panel switch is “on”). Example: Panel switch is “off”. External system sends command “on”. Command is ignored. External system sends command “off”. Command is ignored. Panel switch is switched “on”. Breaker is “on”. External system sends command “off”. Breaker switches “off”.
Breaker doubling and tripling Certain breakers can be joined to create breakers of greater current capability. This is selected via dipswitch profile or in case of programmable profile via the EFIS ECB setup. Choices are: 1+2 1+2 3+4 1+2+3 1+2+3 5+6 In case of programmable profile, trip currents set from EFIS still apply. It is advised that trip currents for joined breakers be set equal. If one breaker in a joined set trips, all breakers in the joined set will trip regardless of each individual breaker current. Notes: Correct current sharing is desired in case of joined breakers. This means equal length and type of wires connected to joint breakers. You can choose either short stubs joined to a common cable or longer cables (of equal length and type) joined further away as is convenient.
Breaker control inputs for doubling/tripling Any breakers selected for doubling or tripling must have their breaker control inputs tied together to a common panel switch or tied to ground if only EFIS control is needed. All LEDs for common breakers will light in the same fashion so if LED indication is required, only one set of LEDs can be used. Leave other LED lines unconnected.
Breaker controls Many options exist when it comes to selecting suitable breaker control switches and indicators. This image shows a ECB control cable made up with the optional switch kit from MGL Avionics. The kit consists of PCB, latching toggle switch, dual color (red/green) LED with chromed bezel and a convenient crimp connector allowing simple connection to the ribbon cable to the ECB. This solution would require two mounting holes in the panel for each breaker.
This image shows one of the switch kit breaker controls in close up.
This image shows popular choices for panel mount switches with built in LED lamps. These typically have a single color LED so you would set the ECB into single LED mode using the programming profile or via the EFIS setup menus.
Breaker profiles 5 of the 8 dipswitches are used to set the desired breaker profile. Profiles choose preset trip currents and breaker doubling/tripling as well as WigWag and Burst flash modes. One profile is available for programming (allows to program certain functions without aid of an external device), one profile is reserved as “programmable” profile – in this case an external device can set breaker and ECB parameters (this is usually the mode chosen if an EFIS is used).
Profile 1 1
2
3
4
5
6
7
8
Breaker
1
2
3
4
5
6
7
8
Joining
No
No
No
No
No
No
No
No
Current
10A
10A
10A
10A
10A
10A
10A
10A
Profile 2 1
2
3
4
5
6
7
8
Breakers 1+2 joined = 20A Breaker
1
2
3
4
5
6
7
8
Joining
2
1
No
No
No
No
No
No
Current
10A
10A
10A
10A
10A
10A
10A
10A
Profile 3 1
2
3
4
5
6
7
8
Breakers 1+2, 3+4 joined = 2 x 20A Breaker
1
2
3
4
5
6
7
8
Joining
2
1
4
3
No
No
No
No
Current
10A
10A
10A
10A
10A
10A
10A
10A
Profile 4 1
2
3
4
5
6
7
8
Breakers 1+2+3 joined = 30A
Breaker
1
2
3
4
5
6
7
8
Joining
2,3
1,3
1,2
No
No
No
No
No
Current
10A
10A
10A
10A
10A
10A
10A
10A
Profile 5 1
2
3
4
5
6
7
8
Breakers 1+2+3, 5+6 joined = 30A + 20A Breaker
1
2
3
4
5
6
7
8
Joining
2,3
1,3
1,2
No
6
5
No
No
Current
10A
10A
10A
10A
10A
10A
10A
10A
Profile 6 1
2
3
4
5
6
7
8
Breaker
1
2
3
4
5
6
7
8
Joining
No
No
No
No
No
No
No
No
Current
10A
10A
10A
10A
5A
5A
5A
5A
Profile 7 1
2
3
4
5
6
7
8
Breakers 1+2 joined = 20A Breaker
1
2
3
4
5
6
7
8
Joining
2
1
No
No
No
No
No
No
Current
10A
10A
10A
10A
5A
5A
5A
5A
Profile 8 1
2
3
4
5
6
7
8
Breakers 1+2+3 joined = 30A Breaker
1
2
3
4
5
6
7
8
Joining
2,3
1,3
1,2
No
No
No
No
No
Current
10A
10A
10A
10A
5A
5A
5A
5A
Profile 9 1
2
3
4
5
6
7
8
Breaker
1
2
3
4
5
6
7
8
Joining
No
No
No
No
No
No
No
No
Current
10A
10A
10A
10A
5A
5A
2A
2A
Profile 10 1
2
3
4
5
6
7
8
Breakers 1+2 joined = 20A Breaker
1
2
3
4
5
6
7
8
Joining
2
1
No
No
No
No
No
No
Current
10A
10A
10A
10A
5A
5A
2A
2A
Profile 11 1
2
3
4
5
6
7
8
Breakers 1+2, 3+4 joined = 20A * 2 Breaker
1
2
3
4
5
6
7
8
Joining
2
1
4
3
No
No
No
No
Current
10A
10A
10A
10A
5A
5A
2A
2A
Profile 12 1
2
3
4
5
6
7
8
Breakers 1+2+3 joined = 30A Breaker
1
2
3
4
5
6
7
8
Joining
2,3
1,3
1,2
No
No
No
No
No
Current
10A
10A
10A
10A
5A
5A
2A
2A
Profile 13 1
2
3
4
5
6
7
8
Breaker
1
2
3
4
5
6
7
8
Joining
No
No
No
No
No
No
No
No
Current
10A
10A
10A
10A
5A
5A
2A
1A
Profile 14 1
2
3
4
5
6
7
8
Breakers 1+2 joined = 20A Breaker
1
2
3
4
5
6
7
8
Joining
2
1
No
No
No
No
No
No
Current
10A
10A
10A
10A
5A
5A
2A
1A
Profile 15 1
2
3
4
5
6
7
8
Breakers 1+2, 3+4 joined = 20A * 2 Breaker
1
2
3
4
5
6
7
8
Joining
2
1
4
3
No
No
No
No
Current
10A
10A
10A
10A
5A
5A
2A
1A
Profile 16 1
2
3
4
5
6
7
8
Breakers 1+2+3 joined = 30A Breaker
1
2
3
4
5
6
7
8
Joining
2,3
1,3
1,2
No
No
No
No
No
Current
10A
10A
10A
10A
5A
5A
2A
1A
Breaker
Breaker
Breaker
Breaker
Breaker
Breaker
Breaker
3
4
5
6
7
8
Function Breaker
Profile 17 1
2
Breaker
3
4
1
5
6
7
2
8
Joining
No
No
No
No
No
No
No
No
Current
10A
10A
5A
5A
5A
5A
2A
2A
Profile 18 1
2
3
4
5
6
7
8
Breaker
1
2
3
4
5
6
7
8
Joining
No
No
No
No
No
No
No
No
Current
10A
10A
5A
5A
5A
2A
2A
1A
Profile 19 1
2
3
4
5
6
7
8
Breaker
1
2
3
4
5
6
7
8
Joining
No
No
No
No
No
No
No
No
Current
10A
10A
5A
5A
2A
2A
1A
1A
Profile 20 1
2
3
4
5
6
7
8
Breaker
1
2
3
4
5
6
7
8
Joining
No
No
No
No
No
No
No
No
Current
10A
5A
5A
5A
2A
2A
2A
2A
Profile 21 1
2
3
4
5
6
7
8
Breaker
1
2
3
4
5
6
7
8
Joining
No
No
No
No
No
No
No
No
Current
5A
5A
5A
5A
5A
5A
5A
5A
Profile 22 1
2
3
4
5
6
7
8
Breaker
1
2
3
4
5
6
7
8
Joining
No
No
No
No
No
No
No
No
Current
2A
2A
2A
2A
2A
2A
2A
2A
Profile 23 1
2
3
4
5
6
7
8
Breaker
1
2
3
4
5
6
7
8
Joining
No
No
No
No
No
No
No
No
Current
1A
1A
1A
1A
1A
1A
1A
1A
Profiles 24-30 are not used If selected, the system will use profile 1
Profile 31 1
2
3
4
5
6
7
8
This profile is called the “programmable” profile. The individual breaker profiles are programmed using an external device. The external device can select trip currents in steps of 0.1A and trip delay times in steps of 0.1 second. It also selects breaker doubling and tripling, WigWag and Burst Flash modes. The external device can program the desired breaker settings regardless of profile selected. However they will only be used if profile 31 is selected.
Programming special functions and modes using the dipswitch Profile 32 (Dipswitches 4,5,6,7,8 “ON”) selects the modules programming mode on application of power. In this mode, the setting of switches 1,2,3 determines selection of a particular mode or function. After application of power the modules green status LED will flash rapidly to confirm the selection. The module will not operate any breakers (they will remain off) and no communications interfaces will be active. After selecting the desired mode and function this way, remove power and reset the dipswitches to the desired profile and reaply power. The dipswitches are only read on power application.
Profile 32 – Set Dual LED 1
2
3
4
5
6
7
8
This profile with switches 1,2,3 set in the above position selects dual LED operation (typically green switch status and red fault status LED, either as two LEDs or a single dual color LED). Place dipswitches in above position and power up the ECB module. The ECB's green LED will flash rapidly to confirm programming completed. You can now remove power and select desired profile.
Profile 32 – Set Single LED 1
2
3
4
5
6
7
8
This profile with switches 1,2,3 set in the above position selects single LED operation (typically green or blue LED, off=breaker off, on=breaker on, flash=breaker faulted (tripped)).
Profile 32 – Set Wigwag ON 1
2
3
4
5
6
7
8
This profile with switches 1,2,3 set in the above position selects WigWag operation on breakers 1 and 2 or 1+2 and 3+4 depending if breaker doubling is selected for 1+2 and 3+4 by choice of profile.
Profile 32 – Set Wigwag OFF 1
2
3
4
5
6
7
8
This profile with switches 1,2,3 set in the above position selects WigWag operation off (normal operation for breakers 1+2 and 3+4 if breaker doubling is selected by profile.
Profile 32 – Set Flasher OFF 1
2
3
4
5
6
7
8
This profile with switches 1,2,3 set in the above position selects the flasher mode OFF. Breakers 5 and 6 resume normal operation.
Profile 32 – Set Flasher ON (Single flasher) 1
2
3
4
5
6
7
8
This profile with switches 1,2,3 set in the above position selects the flasher mode ON for breaker number 5.
Profile 32 – Set Flasher ON (Double flasher) 1
2
3
4
5
6
7
8
This profile with switches 1,2,3 set in the above position selects the flasher mode ON for breaker number 5 and 6. Sequencing is done so at no time will both breakers be on.
ECB node address If the ECB module is used with an external device, it is required to set the node address of the module before connecting to the EFIS CAN bus (or RS232 port in case of third party applications). 8 node addresses are available giving a total of 64 breakers in a system. 1
2
3
4
5
6
7
8
Node address 1, breakers 1-8
1
2
3
4
5
6
7
8
Node address 2, breakers 9-16
1
2
3
4
5
6
7
8
Node address 3, breakers 17-24 1
2
3
4
5
6
7
8
Node address 4, breakers 25-32 1
2
3
4
5
6
7
8
Node address 5, breakers 33-40 1
2
3
4
5
6
7
8
Node address 6, breakers 41-48 1
2
3
4
5
6
7
8
Node address 7, breakers 49-56 1
2
3
4
5
6
7
8
Node address 8, breakers 57-64
Wigwag function The Wigwag function is enabled by using profile 32 programming mode. You can select Wigwag on or off. Wigwag operates on breakers 1 and 2 or joined breakers 1+2 and 3+4 if a profile with doubling is selected. Connect one set to the left wing landing lights and one set to the right wing landing lights. In case of all landing lights in a single wing, consider two sets of landing lights in a wing, each connected to a wigwag breaker set. Wigwag may be operated by panel switch or via EFIS. If operated via EFIS, you can consider bridging the wigwag breaker control inputs to ground (no panel switches or LEDs needed). Note that in case of EFIS failure you will not be able to switch landing lights on or off. In case of ECB failure, the landing lights will be on. The recommended method of wiring Wigwag is to use a single panel switch connected to each wigwag breaker control input. This switch would then ground all wigwag breaker control inputs to switch the landing lights on. On each switch off-on iteration, the mode will change. If the switches are off, the landing lights are off. If on, depending on iteration, the landing lights will be solidly on or they will flash in “wigwag” fashion. This can be used together with remote control from an EFIS if the panel switch is “on”.
Flasher function The flasher function uses breakers 5 or 5 and 6. Each is connected to a high brightness LED, typically a 12V LED or two 12V in series in case of a 24V system. Typical, easily obtainable LED lamps for this are 12V LED down lighters which come in wattage ratings up to 8W giving very bright light. Such a LED uses 1.5 A making it possible to drive as many as 6 of these on a single breaker (or 12 in case of a 24V system). Each breaker flashes three times rapidly within a 1.2 second interval = 50 bursts per second (FAA FAR23 requirements 40-100 per second). The breakers are sequenced so no two breakers will be in the “on” state at the same time so peak current demand is that of a single breaker. Flash “ON” time is 40mS, “OFF” time between flashes of a burst is 40mS. Flasher operation modes (off, single or double breaker) are selected using profile 32 programming procedure.
The 16 pin connectors for LEDs and panel switches The ECB module provides two IDC 16 way connectors with retaining clips.
Each connector serves 4 breakers using 4 conductors: Ground – connects to the power supply negative of the ECB. Common to panel switch and both LEDs. Panel switch – a latching N/O low current switch. Toggle switches or push button switches are common choices. Connects to ground. Status LED. Normally a green LED or the green part of a two color LED. Connect to the anode of the LED, Cathode connects to ground. Note: In single LED operation this line is not used. Fault LED. Normally a red LED or the red part of a two color LED. Connect to the anode of the LED. Cathode connects to ground. Note: In single LED operation this line connects to a green or blue LED.
Preparing a IDC female connector Joining the connector to a flat ribbon cable is done either using a dedicated tool or can easily be done using a common bench vice as shown here. Do not use pliers as it is difficult to use these to apply even force.
A small triangle on the connector denotes “pin 1”. It is not of importance in this application. You can insert the cable from either side of the connector as you wish.
Insert the cable so a few mm shows on the other side. Ensure cable is straight and the connector blades line up exactly with each cable core. Then simply use the vice to squeeze the two connector parts together until they latch.
Close-up of the connector before closing it using the vice. Note how each cable core lines up exactly with its corresponding connector blade. When closed, each blade cuts into the insulation and forces itself around the metal conductor creating a high reliability, gas tight connection. It is important that you ensure the cable is lined up correctly to ensure reliable connections.
Image showing the connector closed. Only a small force is needed when using a bench vice.
Image of a short cable connection ready for use. Split off 4 groups of 4 wires as shown in the image. There is no practical restriction to the length of the cable, you can make it any length you need. The ECB kit contains about 10 feet of 16 way ribbon cable. Contact your supplier if you need longer cable.
Image showing the cable strain relief clip.
Fold the cable over the top of the connector and insert the train relief clip until it latches on both sides.
Image showing connector with strain relief clip inserted in one of the ECB connectors. The two restraining clips clip over the strain relief and hold the connector securely in place. To remove the connector, simply force the two clips apart - this levers the connector out. Note that you can insert the cable into the connector from any direction so you can choose the cable exit path as your needs dictate.
Identifying connections
Interface to an external device The ECB provides two types of interface:
RS232 The RS232 port contains a RX (receive) and a TX (transmit) line. In case more than one ECB is used in a system, the ECB modules are daisy chained. This means the TX line of one module goes to the RX line of the next module. Each module must have a unique address set with dipswitches 1,2 and 3. The modules may be wired in any order. The RX of the first module and TX of the last module in the chain is then wired to the external device. Note: The RS232 interface is NOT used with MGL EFIS systems and can be left unconnected.
CAN bus Note: In MGL EFIS systems the CAN bus is used to connect to the ECB. Up to 8 ECB modules giving a total of 64 breakers may be connected. You must set each module to a unique address using dipswitches 1,2 and 3. The CAN bus consists of two conductors that should form a “twisted pair”. One conductor is called “CAN-High”, the other “CAN-Low”. The CAN bus is wired to all devices taking care that all device CAN-High connections are wired to the bus line “CAN-High” and device CAN-Low are wired to the bus line “CAN-Low”. The CAN bus forms a single twisted pair cable going from device to device with only short stubs (1 ft, 30cm or less) permitted for each device connection. In order to operate the CAN bus must be terminated with two resistors. Each end of the CAN bus must have a 120 ohm resistor wired from CAN-High to CAN-Low. For short runs typical in
a small aircraft it is permissible to use just a single resistor of 60-100 ohm value anywhere on the bus between CAN-High and CAN-Low. It is permissible to use shielded cable containing the two CAN bus wires. In this case it is recommended that the shield be connected to ground at a single location only (so no currents can flow through the shield).
CAN bus primer The CAN bus (Controller Area Networking) was defined in the late 1980 by Bosch, initially for use in automotive applications. It has been found to be very useful in a wide variety distributed industrial systems and is becoming popular in avionics applications due its robustness and ease of use.
The connection uses two wires which are twisted around each other. This forms a “balanced transmission line”. It helps to reduce emissions and also makes the link more robust against external interferences. The CAN bus is always implemented as a single cable allowing only short stubs to connect to equipment along the route. Never implement a CAN bus as a “star” or other wiring topology. The CAN bus requires termination resistors at each end of the bus. These are to be 120 ohm resistors. 1/4W or 1/8W resistors are usually used here. The resistors must be installed at each end of the bus, not in the center or anywhere else. For short CAN runs (less than three meters) it is possible to install a single resistor of lesser value (not less than 60 ohms) at any location in the cable run. The two wires are referred to “CAN High” and “CAN Low”. These must connect to the corresponding lines at the devices. Never swap these connections (I.e. Never connect CAN H to CAN L at any device) as the CAN bus will not be able to function. Never run the CAN bus connection inside a wire harness next to sensitive connection such as audio or signal wires. Never run the CAN bus next to RF cables.
Making twisted wire It is very easy to make your own twisted wire. Simply take two equally long wires (for example 5 meters) in parallel and tie one end (both wires) to a fixture (a door handle works well). Insert the other end (both wires) into a drill. Stretch the wires so they are straight. Run the drill for a few short bursts at slow speed and you have a created a perfect twisted pair !
Shielded, twisted wires It is possible to purchase shielded, twisted wire. This can be used in applications where there may be electrical noise issues. In this case we advise to connect the shield to ground AT A SINGLE LOCATION ONLY. This prevents creating a “ground loop” which can cause EMI issues.
Basic wiring checks You can use a volt meter to perform basic checks on a CAN connection. With at least one device connected and powered you should be able to measure voltages of around 1.0 – 3.0 volts on each cable with respect to ground. The voltage should appear very similar on each connection.
Technical data Breaker Maximum continues DC current through each breaker: 10A Maximum current through each breaker: 45A (ultimate trip current) Maximum die temperature of each breaker: 165 degrees Celsius. Breaker will switch off when reaching this temperature. Breaker clamp voltage: 65V (if input voltage rises above output voltage by 65V the breaker will start conducting and attempt to clamp the voltage at 65V in order to protect itself. Trip currents depend on selected profile. Trip times for profiles other than profile 31 (programmable profile) are fixed to 0.5 seconds multiplied by the inverse of the over current ratio. For profile 31 trip times are programmable from 0 seconds in steps of 0.01 second. Example: Breaker trip current = 5A, trip time 0.5 seconds, breaker current = 5A. Trip time = 5/5*0.5 = 0.5 seconds Example: Breaker trip current = 5A, trip time 0.5 seconds, breaker current = 10A. Trip time = 5/10*0.5 = 0.25 seconds Example: Breaker trip current = 5A, trip time 0.5 seconds, breaker current = 20A. Trip time = 5/20*0.5 = 0.125 seconds Currents during the over-current time period are integrated accordingly. Breaker features “soft start” to protect equipment from sudden rise of voltage. Soft start characteristics: Turn on time to 20% of Voltage: 35uS typical. Rise time from 20% to 80% of Voltage: 17uS typical.
Replacement semiconductor switch element: AUIPS7111S, International Rectifier. Note: Please use Automotive qualified parts only.
ECB module general Maximum total continues input current through input terminal: 60A Maximum total instantaneous current through input terminal (1 second): 150A Maximum voltage with respect to ground on breaker input and output: 35V DC Supply voltage for ECB (on D9 connector): Maximum 35VDC. Supply current @13.8VDC is under 50mA. Note: Supply current for ECB will be taken either from the breaker input terminal or the supply pin 4 on the D9 connector depending on which voltage is the higher.
Control interface Switch current (switch closed): 3mA Switch voltage (switch open): 2.6V (up to 3.3V if zero load).
LED outputs 3.3V via 68 ohm resistor into anode of LED, cathode at 0V. Typical currents depend on LED threshold voltage and are in the order of 20mA.
RS232 port Baudrate 38400, 8 data bits, 1 stop bit. Daisy chain topology if more than one breaker used in system. Up to 8 ECB modules in a daisy chain. Please contact MGL Avionics if protocol information is required.
CAN port Implements CAN 2.0 with 11 bit identifiers at 250KBaud. Up to 8 ECB modules may be connected to one CAN bus. For protocol information please view MGL CAN bus protocol document available for download on MGL Website: www.MGLAvionics.co.za
Installation guidelines The ECB module must be installed in a well ventilated area. Avoid confined spaces with no airflow that may give rise to excessive temperatures. Install a fan to promote airflow if no other solution is possible. Avoid locations where high ambient temperatures may be encountered. Excessive temperatures may reduce the maximum current capability of the ECB. Avoid locations where excessive vibration may be coupled onto the ECB module or any attached wiring. Only use conductors that are able to handle the expected currents without excessive self
heating. Ensure cable insulation retains required properties over time and temperature. Ensure that all terminals are secure and are protected against vibration in an adequate manner. Ensure no cables will chafe against airframe parts so cable insulation may be damaged. Ensure all cables and connections are adequately insulated and protected against corrosion as needed.
Comparison between mechanical and electronic circuit breakers The ECB (Electronic Circuit Breaker) is a replacement for the traditional mechanical circuit breaker. Mechanical breakers use heat created by the current through a resistive wire to bend a bimetal part that unlatches a switch if a certain temperature is reached. The time it takes for the breaker to “trip” depends highly on ambient temperature, the amount of current through the breaker as well as mechanical tolerances which can be great. Long term effects on materials and wear also have a large influence. Time/Current/temperature curves are usually published by manufacturers of these breakers. Electronic breakers do not have any of these issues. As no power needs to be drawn from the current source to heat a wire the electronic breakers tend to have a very low “on” resistance (in case of this product at little as 0.003 ohms). This means less heat and near zero power loss over the breaker. Breaker trip points are now controlled by a microprocessor as well as an ultimate trip point in case of microprocessor failure. Due to this trip points are tightly defined and trip behavior and times are well defined. Unlike mechanical breakers, trip times can now be made much shorter offering better circuit protection and enhanced safety.
The ECB has a default trip time of 0.5 seconds which is shortened as current increases. This allows the ECB to absorb typical inrush currents when equipment is switched on which may exceed normal operating currents while still offering much superior protection. Using the EFIS programmable profile longer or shorter trip times may also be set depending on needs. Comparison of mechanical to electronic breaker (from manufacturer data of a FAA certified mechanical breaker – times stated here do not take into account tolerances which are large) Of rated current
Mechanical breaker
Electronic breaker (default)
100.00%
>100 seconds
0.5 seconds
200.00%
~ 10 seconds
0.25 seconds
400.00%
~ 2 seconds
0.125 seconds
1000.00%
~ 0.3 seconds
0.05 seconds
Mechanical breakers have a lifetime restriction of 5000 actions on a typical load, electronic breakers are not limited in the number of actions. ECB modules allow decentralization of power switching and overcurrent protection. It is not required any longer to wire high current conductors behind the panel, instead low current, reliable latching switches, LED indication which is visible in darkness and small diameter, low current wiring is used. ECB systems, when connected to an EFIS system allow display of individual breaker states (on, off, faulted) and currents measured through each breaker. Depending on configuration the EFIS may also be used to switch breakers and reset fault states. Having the ability to show currents through each breaker at any time is an invaluable diagnostics tool for any aircraft's electrical system.
Environmental compliance of the ECB module DO-160 compliance statement based on Do-160D Temperature and Altitude
4.0
Equipment intended for use with categories A4, C4
Low temperature ground survival (declared)
4.5.1
-55°C
Low temperature operating (declared)
4.5.1
-20°C
High temperature operating (declared)
4.5.3
+55°C
High temperature short-time operating (declared)
4.5.2
+70°C
High temperature ground survival (declared)
4.5.2
+85°C
Loss of Cooling
4.5.4
No cooling required
Altitude
4.6.1
No restriction
Decompression
4.6.2
No restriction
Overpressure
4.6.3
No restriction
Temperature Variation
5.0
Equipment complies with Category C
Humidity
6.0
Equipment complies with Category A
Operational Shocks
7.2
Equipment complies with Category B
Crash Safety
7.3
Equipment complies with Category A
Vibration
8.0
Compiles with Categories S, R
Explosion
9.0
Not applicable
Waterproofing
10.0
Not applicable
Fluids Susceptibility
11.0
Not applicable
Sand and Dust
12.0
Not applicable
Fungus
13.0
Not applicable
Salt Spray
14.0
Not applicable
Magnetic Effect
15.0
Not applicable
Power Input
16.0
Equipment complies with Category B
Voltage Spike
17.0
Equipment complies with Category B
Audio frequency conducted susceptibility
18.0
Equipment complies with Category B
Induced signal susceptibility
19.0
Equipment complies with Category AC
Radio frequency susceptibility
20.0
Equipment complies with Category T
Radio frequency emission
21.0
Equipment complies with Category B
Lightning induced transient susceptibility
22.0
Not applicable
Lightning direct effects
23.0
Not applicable
Icing
24.0
Not applicable
Electrostatic Discharge
25.0
Category A on breaker inputs and outputs
DO178D software assurance statement for ECB module The firmware in the ECB is designed according to DO178 level D guidelines related to: Software life cycle Firmware update distribution Firmware update procedures Software functional testing and validation ECB breaker control ECB breaker current monitor ECB breaker fault detection and control ECB breaker special functions CAN and RS232 protocol tests and validation Storage and retrieval of setups Software recovery in case of external or internal induced malfunction Firmware update process and correctness of code checks Software documentation Procedures Program flow Parameters and returns Data structures Protocols
DO254 electronic hardware assurance statement for ECB module The ECB hardware is designed based on DO-254 guidelines: Hardware design life cycle Design iterations – Flow Hardware design process Steps from concept to prototype for each iteration Validation and verification process Testing and verification of actual functionality and electrical performance against design goals Transfer to production process
Notes on DO-160, DO-178, DO-254 statements in this document The ECB module is intended for use in non-type certified aircraft or any aircraft where fitting of non-approved equipment is permitted or requires additional approvals (modification approval or STC). Documents DO-178 and DO-254 referred to here provide guidelines on the process of certification which would involve at an early stage the certification authority. This has not been adhered to as there is no intention of certifying this equipment. However, the documents retain their validity and have nevertheless been used as foundation to the design of this equipment. Document DO-160 however is different in that it specifies and details the process of numerous tests to be performed on the equipment. These tests have been carried out under self-certification rules as part of the design verification and the results published in this document.
